ジャーナル: Nat Commun / 年: 2023 タイトル: Organisation of the orthobunyavirus tripodal spike and the structural changes induced by low pH and K during entry. 著者: Samantha Hover / Frank W Charlton / Jan Hellert / Jessica J Swanson / Jamel Mankouri / John N Barr / Juan Fontana / 要旨: Following endocytosis, enveloped viruses employ the changing environment of maturing endosomes as cues to promote endosomal escape, a process often mediated by viral glycoproteins. We previously ...Following endocytosis, enveloped viruses employ the changing environment of maturing endosomes as cues to promote endosomal escape, a process often mediated by viral glycoproteins. We previously showed that both high [K] and low pH promote entry of Bunyamwera virus (BUNV), the prototypical bunyavirus. Here, we use sub-tomogram averaging and AlphaFold, to generate a pseudo-atomic model of the whole BUNV glycoprotein envelope. We unambiguously locate the Gc fusion domain and its chaperone Gn within the floor domain of the spike. Furthermore, viral incubation at low pH and high [K], reminiscent of endocytic conditions, results in a dramatic rearrangement of the BUNV envelope. Structural and biochemical assays indicate that pH 6.3/K in the absence of a target membrane elicits a fusion-capable triggered intermediate state of BUNV GPs; but the same conditions induce fusion when target membranes are present. Taken together, we provide mechanistic understanding of the requirements for bunyavirus entry.
想定した対称性 - 点群: C3 (3回回転対称) / 解像度のタイプ: BY AUTHOR / 解像度: 13.0 Å / 解像度の算出法: FSC 0.5 CUT-OFF 詳細: Subtomogram averaging was performed focusing on the floor region at the base of the tripod glycoprotein spike. 使用したサブトモグラム数: 16096
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トモグラム数: 14 / 使用した粒子像数: 20490
最終 角度割当
タイプ: OTHER / 詳細: PEET software used - 3D reference matching